Strong acid anion exchange resin Amberlite IR400 (Cl⁻) has been modified by sorption of cresol red. Equibration studies such as concentration, pH, time and temperature of the reagent on the adsorption of dye have been studied. The maximum uptake of cresol red was found to be 2.20 µmol per 0.3 x 10³ g resin at pH 1.0. On the basis of Kd values in solvents having different polarity and dissociation constant, important binary separations of metal ions namely Pb²⁺, Bi³⁺, Mn²⁺, Zn²⁺, Ni²⁺, Sn⁴, Hg²⁺, Mg²⁺, Zr4+, Ca²⁺, Ba²⁺ and Sr²⁺ have been achieved. To check the selectivity and the reproducibility of the method, separation of different amounts of Hg²⁺ has been achieved in a synthetic mixture containing Fe³⁺(5.58 mg), Cu²⁺ (6.35 mg), Al³⁺ (2.69 mg) and Ni²⁺ (5.68 mg). The results show that the cresol red modified resin may be used for the removal of Hg²⁺ from industrial and domestic wastes. Results also indicate that the modified resin may also be suitable as a packing material in column chromatography for pre-concentration and recovery of some metal ions from industrial effluents and wastewater.